Work has continued on the development of bifunctional antitumor agents, made up by the complexation of a platinum containing moiety and a biologically active ligand, such as adriamycin. In the present phase of this work, tritiation of cis-dichlorodiammine platinum(II) has been achieved and a novel method of tritium electrophylic substitution has been developed. This process allows the tritiation of the non-exchangeable protons on the ammonia ligand at acidic pH, to give a tritiated product that is non-exchangeable at physiological pH. Work has also continued on the subcellular localization and disposition of 195mPt-cis-DDP in the kidneys; the specific binding of cis-DDP to the lysosome of the proximal tubule has been further documented. The distribution of various platinum complexes has revealed several interesting patterns of localization, noticeably the continued high uptake of platinum by the skin, as well as its fluctuation, suggesting the presence of an exchangeable reservoir pool whose significance in terms of chemotherapy has yet to be evaluated. Methodological problems were encountered in the synthesis of complexes between adriamycin and various platinum compounds because of scaling down and new chromatographic methods of separation and identification of such complexes have been developed.